1. Field of the Invention
The present invention relates to a flying body that levitates and flies in the air. This invention relating to a flying body is applicable to a toy aircraft as well as a manned aircraft and an unmanned aircraft.
2. Description of the Related Art
A conventional flying body operates propellers, a jet engine, a rocket engine or the like to produce thrust that propels the vehicle body forward, so that the wings travel relative to the air. This relative movement generates airflows on the upper and lower wing surfaces, thus producing aerodynamic lift that levitates the flying body. Accordingly, the flying body is required to be propelled forward at all times for producing the aerodynamic lift. As a result, the flying body cannot stop or hover in the air, except in special cases. If the flying body cannot move forward, the loss of aerodynamic lift results, and the crashing of the flying body because of stalling is unavoidable.
By contrast, a helicopter rotates its wings to move them relative to the air in order to produce aerodynamic lift for levitation. Accordingly, the helicopter can stop or hover in the air. However, since the rotor has a size much larger than that of the helicopter body and rotates outside the helicopter body, the rotor is vulnerable to external obstructions, involving the risk of damage. In consequence, there is a disadvantage of the helicopter being subjected to restraints in its operational environment.
Hence, for eliminating this disadvantage, a flying body equipped with a plurality of rotors arranged within the projection contour of the vehicle body as viewed from above is suggested (Patent Document 1). Patent Document 1: Japanese Patent application Laid-Open No. 2004-82999, the entire contents of which are incorporated herein by reference.
Also, an invention designed to provide a fan in the center inside a ring-shaped wing for blowing air in a centrifugal direction for levitation is disclosed (Patent Document 2). The invention assumes the principle of having a ring-shaped wing and radially blowing air from a fan which sends air in the centrifugal direction toward the ring-shaped wing in order to produce aerodynamic lift that generates an air flow on the ring-shaped wing. Patent Document 2: Japanese Patent application Laid-Open No. 2004-168276, the entire contents of which are incorporated herein by reference.
The flying body disclosed in Patent Document 1 has the problem of the incapability of producing adequate aerodynamic lift unless a high output engine is employed, because of the limited size of the rotor housed in the vehicle body.
On the other hand, the flying body disclosed in Patent Document 2 is based on a design in which the fan disposed inside the ring-shaped wing takes in air from the central upper direction or the central up-down direction and sends it toward the ring-shaped wing in the radial direction. As a result, the wing comes into contact with the air flowing from above the wing in the center hole, and the aerodynamic lift is counteracted by the air taken in from below the fan. In other words, when the vehicle body is immobilized in a fixed position, the aerodynamic lift can be produced, but when a load is actually applied to the vehicle body, an amount of air current corresponding to the applied load escapes from the gap between the fan and the center hole of the wing in a direction opposite to that of the load applied. As a result, even if aerodynamic lift is produced on the wing cross-section, an air flow corresponding to the load escapes from the upper side of the fan toward the upper wing surface. Thus, the flying body cannot levitate.